1. Field of the Invention
This invention resides in the area of apparatuses and methods used for the determination of melting points of materials and more particularly relates to an apparatus and method which determines the melting point of a sample material by measuring temperature changes of the material until the thickness of the sample material goes to zero under pressure.
2. Description of the Prior Art
Many methods are used to determine melting points of materials. The simplest are types where observers note temperatures at which materials, upon heating, become transparent such methods first involve immersing the particle of material whose melting point is to be determined in a non-solvent which is heated at a known rate. As the heat from the medium is transferred into the particle, at the point where the temperature of the medium is equal to the melting point of the particle, the particle changes its optical transmissibility and also may change its physical shape. The automated recording of temperature while an observer monitors the reflectivity of infrared light directed at material is disclosed in International Application No. PCT/GB90/00751. A problem with many of these prior art melting point determination apparatuses is that they lack accuracy in that they require the judgment of an observer as to when a reaction has taken place, and this judgment can vary from observer to observer.
U.S. Pat. No. 5,092,679 by the present inventor disclosed an apparatus and method that automatically records measurements of both light reflectivity or transmissivity and temperature of a material to determine its melting point. The invention also disclosed means for recording deformation of materials at various pressures.
A November, 1991 article in Laboratory Equipment Digest entitled "Faster and Simpler Melting Point Measurement" described a melting point device which measures the reflectivity of near-infrared light directed at a material, which material rests on a plate of borosilicate glass heated from below by a flat film strip heater. A problem with many of the prior art apparatuses is that they require a light source and measure the reflectivity of light directed at the sample material.